Fin plate for tube and plate fin cores and method for manufacturing thereof



3,305 HOD M. L. JENTET Feb. 21, 1967 I 1 FIN PLATE FOR TUBE AND PLATE FIN corms AND MET FOR MANUFACTURING THEREOF 2 Sheets-Sheet 1 Filed- June 22, 1964 F i e13 .v

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Fla-6 4 FIG INVENTOR NAXI'ME L.

JENTET Feb. 21, 1967 M. L. JENTET 3,305,009

FIN PLATE FOR TUBE AND PLATE FIN CORES AND METHOD FOR MANUFACTURING THEREOF" Filed June 22, 1964 2 Sheets-Sheet 2 MAxiME 1.. JE'NTET R i Y O w \I T H IKIJ 0 n1 11/. N A 4 4/ 44M \rv/ W V L 5/ ,2 \\x a 2 m flJ United States Patent 3,305,009 FIN PLATE FOR TUBE AND PLATE FIN CORES A N D METHOD FOR MANUFACTURING THEREOF Maxime Louis Jentet, Chatou, Seine-et-Oise, France, as-

signor to Societe Anonyme des Usines Chausson, Asnieres, France, a company of France Filed June 22, 1964, Ser. No. 376,709 Claims priority, application France, June 27, 1963, 939,619, Patent 1,386,228; Dec. 16, 1963, 957,356 3 Claims. (Cl. 165-151) For many years past, radiator cores have been made comprising tubes which are engaged in a set of fins respectively placed at regular intervals which must be determined with a relatively close accuracy so that the heat exchange takes place in good conditions. In certain cases, for determining the pitch of fins, i.e., the space separating successive fins, lugs or points also called spacers are made in them between the tube passage opening that they possess, projecting to an extent which corresponds to said space to be obtained. This arrangement is satisfactory in certain cases, more particularly when the tubes are relatively spaced out between them and when the fins are sufficiently thick so that they do not risk bending and being distorted at the moment when the tubes are engaged in the openings between the flange or collar provided to receive them; in most cases, however, these spacers have wellknown disadvantages, more particularly, their influence is unfavourable as the part of the fin forming the spacer has, starting from the wall of the tube which diffuses the heat, a length greater than the half-distance between two consecutive tubes. This means that the efficiency of this part of the fin, i.e., in other words its mean temperature, falls below the efficiency of a similar fin not comprising a spacer. This lowering of efiiciency is the more important seeing that the spacing of the fins is greater and that the metal of the fin is not such a good heat conductor, which is the case of fins made of steel generally used on radiator cores of motor vehicles manufactured by mass production. It has been proposed, for obviating this disadvantage, to suppress the spacers by a mutual strutting of fins by means of cambered lugs i.e. lugs folded at their free end formed crosswise to the collar bordering the passage openings of tubes, i.e., formed at the front and rear parts of said tubes. Such a known structure may be found for instance in British Patent No. 664,582. This embodiment has given good results up till now, but proves to be inapplicable today, allowing for the progress made in the technique of cooling radiators, for the tubes now employed are very thin ones, whose thickness is in the region of 2 rnm., and consequently, the known lug or tongue formed crosswise to the collar of the tube passages in the fins, a lug whose width is necessarily smaller than that of said passage, can no longer have sufficient mechanical strength for ensuring the regular strutting of fins at the moment when they are positioned by inserting the tubes. Actually, seeing that the tubes passage has a width of about 2 rnm., the upper end of the tongues or lugs that are known would have a lesser width, of about one millimetre, and it is obvious for anyone experienced in this technique that said logs or tongues have thus practically no strength, and in any case, much less than the stresses that they should bear when the tubes are engaged in the bundle of fins.

The present invention obviates this disadvantage by creating a new fin for tube and plate fin cores and a method for the manufacturing of said fin.

According to the invention, the fin plate has a number of passage openings for tubes corresponding to the number of tubes that this core must comprise, these openings 3,305,009 Patented Feb. 21, 1967 being also made in positions also corresponding to the arrangement that said tubes must occupy, and each opening of general rectangular shape with rounded ends is bordered on each of its large sides by rectangular collars extending at right angles in relation to the plane of the fin, one at least of the collars being integral with a spacer extending in the prolongation of said collar and whose length is equal to the spacing there must be between the fins of the assembled core, whereas its width is determined by the stress to be borne.

Various other characteristics of the invention will moreover be revealed by the detailed description which follows.

Forms of carrying out the invention are shown by way of non-restrictive examples in the attached drawings.

FIG. 1 is a partial diagrammatical elevation of a radiator core according to the invention.

FIG. 2 is a partial plane view, on a larger scale, of a fin showing a manufacturing stage.

FIG. 3 is a plane view corresponding to FIG. 2, showing another manufacturing stage.

FIG. 4 is a section taken along the line IV-IV of FIG. 3.

FIG. 5 is a partial plane view on a smaller scale, of a fin showing a supplementary detail.

FIGS. 6 and 7 are plane views respectively corresponding to FIGS. 2 and 3 and showing a slight modification.

FIGS. 8 and 9 are plane views similar to FIGS. 6 and 7 of another modification. v

FIG. 10 is a partial plane view seen from above of a fin according to the present invention.

FIG. 11 is a section taken along the line XIXI of FIG. 10.

FIG. 12 is a section taken along the line XIIXII of FIG. 10.

FIG. 1 shows diagrammatically a radiator core which comprises tubes 1 for the circulation of a cooling liquid, these tubes 1 being thermally connected together by fins 2 the spacing of which is constant and determined by spacers formed directly from the fins, these spacers not being intended to modify the particular structure of the fins in their parts located between the successive tubes 1 so that said parts called intermediate of the fins can be variously shaped for improving their thermal efficiency as stated in that which follows.

According to the invent-ion, for making the struts or spacers that must define the spacing of the fins, i.e., their respective distance apart, one proceeds as follows: In FIG. 2, each of the fins is subjected to a cutting operation which is made at the place that the tubes must subsequently occupy, this cut having a rectilinear segment 3 whose ends are joined to two opposite cuts 4, 5 made along the three sides of a rectangle, these cuts, called rectangular outs, being themselves prolonged by curved cuts 6. The number of cuts made in each fin corresponds to the number of tubes which must pass through said fins. After the cutting operation, a folding or bending operation is carried out which has the effect of raisin-g the two edges defined by the cut 3 on one side of the fin. Slots 7 are thus made of general rectangular shape bordered on each of their two large sides by collars 8, 9 whose height corresponds to halfthe width of the slot 7, the two collars 8, 9 being respectively prolonged by projecting spacers 10 and 11 which have been defined by the opposite rectangular cuts 4, 5 and whose height corresponds to the spacing that the fins must have between them. As will be seen in FIG. 3, the curved cuts 6 have the effect of providing in the fins 2 solid parts 12 which are below the spacers 10 and 11, when the latter are raised after the folding operation, these solid parts thus forming bearing points for the spacers 10, 11 of the contiguous fin, so that there is no risk of a spacer can be penetrated into the slots of another fin.

The spacers or strutte-d lugs being placed at the two ends of the tubes 1 engaged in the slots 7, and these spacers being integral with the collars 8, 9 in which the tubes are tightened, said lugs are thus placed at least partly against the tubes, so that their resistance to fiexure, i.e. distortion along their longitudinal axis upon compression stresses, is good even when the fins are very thin and made of relatively soft metal like copper or aluminium. Moreover, the spacers 10, 11 being arranged in a contiguous position in relation to the tubes, it results, at the moment when the latter are engaged in a bundle of fins for making up the core of FIG. 1, that the intermediate parts of said fins, i.e., the parts extending between two consecutive tubes, do not run the risk of bending, and also these parts are left completely free, which enables them to be shaped, for example, as shown at 13 in FIG. 5, so as to increase their heat yield, more particularly by folding them or by providing shutters or slits, which ensures a better evacuation of the calories that said fins must dissipate.

The method of embodiment according to FIGS. 2 to 4 requires that the spacing of the fins be greater than the thickness of the tubes of the core. When this spacing, on the contrary, is smaller or equal to the thickness of the tubes of the core, one proceeds as shown in FIGS. 6 and 7, or in FIGS. 8 and 9. According to FIGS. 6 and 7, the cuts 4 are made and a first fold is made along the line 14 so as to define a shoe at the ends of the spacers 11, intended to make a bearing surface for the contiguous fin, and in this way the spacer 11 is shorter and can have any required height.

According to FIGS. 8 and 9, a semi-rectangular section 4a is made at the end of the cut rectilinear section 3, and the curved cut 6 is prolonged by a rectilinear section 6a extending as far as the place that the opposite collar must occupyin this case, the collar 8-after the latter has been raised by the folding operation. Thus, a spacer 11a is defined, similar to the spacer 11 of FIGS. 2 to 4, but whose height can be appreciably less than the width of the .slots 7 into which tube must pass.

' According to 'FIGS. 10 to 12, the operation for folding the collars 8, 9 and lugs 10 and 11, and shaping the spacers, is carriedout so that these lugs 10, 11 do not extend parallel to the tubes 1, but separate each tube according to an angle of about 10, for example. This arrangement is particularly well shown in FIG. 11.

Also, as shown in FIG. 10, the lugs 10, 11 are, over the greater part of their extend, slightly arched so as to increase their rigidity.

Seeing that the spacers 10 and 11 diverge from the wall of the corresponding tube, they do not risk penetrating between this tube and the edge of the slot 7 of the immediately contiguous fin. For the same reason, it has been found advantageous also to provide an alternation in the arrangement of the lugs 10, 11. Actually, as shown more particularly in FIG. 10, the lugs 10 are raise-d towards the right of each slot 7 whereas the lugs 11 are raised to the left of these slots.

Moreover, two successive slots of the same fin have their lugs 10 and 11 which are alternated so that when n fins are piled one on the other, each spacer 10 is underneath a spacer 10, whereas each spacer 11 is underneath a spacer 11, as shown in FIGS. ll and 12.

This arrangement, associated with the arching of the lugs 10, 11, means that a continuity is obtained in assembling fins, for this arch imparted to spacers, in addition to increasing their rigidity, provides a wider contact 7 surface for these spacers with the upper fin.

, The part of the fins between successive collars 9, 8 is cut to provide points defining shutters 25 all identical to each other. The successive groups of shutters are nevertheless offset, as shown in FIG. 10, in the flow direetion of the air, so as always to provide a minimum metal width l between the cuts of the shutters and the cut defining the slots 7, so that the fin retains a sufiicient solidity and that throttling zones are not created for the passage of calories, but that, on the contrary, thermal diffusion can take place in as homogenou-s a manner as possible in all par-ts of the fin.

When the radiator core comprises, as is nearly always the case, several successive rows of tubes-in the example shown, two rows-the incidence of the shutters 9 of group a (FIG. 12) is opposed to the incidence of the shutters 9 of group b, so that the course of the air passing through the shutters is appreciably that shown by the arrow 1.

To still further improve the thermal etficiency of the fin and also to increase the rigidity of the edges of each fin, small stampings or bosses 26 (FIG. 10) are made on the front and rear edges of each fin, in the direction of the air flow, these stampin-gs being fairly close together; for example, a stamping is provided in front of each tube and a stamping in front of each group of shutters.

In order to diiferentiate the front from the rear edge of the fin, for the purpose more particularly of facilitating manufacture to be able easily to locate the position that the fins must occupy during their assembling in bundles before putt-ing the tubes in place, it is advantageous that the front edge, for example, of the fin should not have the same series of stampings .26, more particularly one stamping in ten can be suppressed on the front edge, as shown at the bottom part of FIG. 10.

The fins being made from very thin strips, it is of course important that they have a sufiicient rigidity so that they are not distorted at the moment when the core is made up. For this, there is made in each fin, between two successive rows of slots for receiving the tubes 1, a shallow longitudinal corrugation 27, so as not to interfere with the air flow; by way of example, this corrugation can have a width of about 2 mm. and a depth of 0.3 mm. It is advantageous that said corrugation 'be made on the strip, during the work, which must form each fin in the first shaping operation, so that this corrugation acts for guiding the strip under the working tools which must then effect the cuts and cambers leading to the forming of the collars, spacers and shutters.

Although from the purely thermal point of view, it is not greatly important that the projections made by the collars, 8, 9, the spacers 10, 11 and the shutters 25 be directed on one or the other side of the plane defined by each fin, it is advantageous from the manufacturing standpoint, and this is another characteristic of the in vention, that all these projections be formed on the same side of the plane defined by the fin, for, thus it is possible to obtain an easy sliding of the fin on the shaping tool or tools, which would not be the case if the shutters were cut and cambered on one of the sides of the fin, whereas the collars and spacers would be cut on the other side of the fin.

The invention is not restricted to the examples of embodiment shown and described in detail, for various modificat-ions can be applied to it without going outside of its scope.

I claim:

1. The combination, with a plurality of tubes of oblong cross section in a cooling radiator core, of a fin plate assembly comprising:

a plurality of thin, substantially flat plate members of heat conductive material, the plate members each having a plurality of passage openings, having a given length, formed therein, there being one such opening for each of the tubes of an assembled core in each of the plate members thereof;

the openings being spaced in the plate members in positions corresponding to the desired locations of the tubes;

the openings being of substantially rectangular form with rounded ends, and having elongated sides,

a substantially rectangular flange immediately adjacent each of said longitudinal sides and arranged in substantially right angular relation to the plate members and having ends;

a spacer extension for each flange, secured thereto and projecting from opposite ends of adjacent flanges, the spacer extensions extending from the plate members for a desired distance between adjacent stacked plate members of the assembled core;

the total spacer contact length being a small portion of the length of the tube opening; and

the spacer extensions for said openings being diagonally opposed with respect to each other.

2. The combination of claim 1, and:

the spacer extensions being arched about their respective longitudinal axes whereby their rigidity is increased, and they are constantly in contact with a solid portion of an adjacent plate member.

3. The combination of claim 2, and:

a series of shutters between each adjacent pair of openings in each plate;

the series of shutters being arranged in offset rows to vent a maximum area of the plate members; and

the shutters of successive rows being oppositely inclined.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS Austria.

Great Britain. Great Britain. Great Britain. Great Britain.

ROBERT, A. OLEARY, Primary Examiner.

CHARLES SUKALO, Examiner.

25 A. W. DAVIS, Assistant Examiner. 

1. THE COMBINATION, WITH A PLURALITY OF TUBES OF OBLONG CROSS SECTION IN A COOLING RADIATOR CORE, OF A FIN PLATE ASSEMBLY COMPRISING: A PLURALITY OF THIN, SUBSTANTIALLY FLAT PLATE MEMBERS OF HEAT CONDUCTIVE MATERIAL, THE PLATE MEMBERS EACH HAVING A PLURALITY OF PASSAGE OPENINGS, HAVING A GIVEN LENGTH, FORMED THEREIN, THERE BEING ONE SUCH OPENING FOR EACH OF THE TUBES OF AN ASSEMBLED CORE IN EACH OF THE PLATE MEMBERS THEREOF; THE OPENINGS BEING SPACED IN THE PLATE MEMBERS IN POSITIONS CORRESPONDING TO THE DESIRED LOCATIONS OF THE TUBES; THE OPENINGS BEING OF SUBSTANTIALLY RECTANGULAR FORM WITH ROUNDED ENDS, AND HAVING ELONGATED SIDES; A SUBSTANTIALLY RECTANGULAR FLANGE IMMEDIATELY ADJACENT EACH OF SAID LONGITUDINAL SIDES AND ARRANGED IN SUBSTANTIALLY RIGHT ANGULAR RELATION TO THE PLATE MEMBERS AND HAVING ENDS; A SPACER EXTENSION FOR EACH FLANGE, SECURED THERETO AND PROJECTING FROM OPPOSITE ENDS OF ADJACENT FLANGES, THE SPACER EXTENSIONS EXTENDING FROM THE PLATE MEMBERS FOR A DESIRED DISTANCE BETWEEN ADJACENT STACKED PLATE MEMBERS OF THE ASSEMBLED CORE; THE TOTAL SPACER CONTACT LENGTH BEING A SMALL PORTION OF THE LENGTH OF THE TUBE OPENING; AND THE SPACER EXTENSIONS FOR SAID OPENINGS BEING DIAGONALLY OPPOSED WITH RESPECT TO EACH OTHER. 